The present invention relates to a divers"" information display device. More particularly, this invention is concerned with a technology preferable for a display device which is an integral part of an information processing apparatus and on which a time instant indication and various diving-related indications are mutually changed and selectively displayed.
Wristwatches having an added ability relevant to diving and intended for divers have been locally available in the past. This sort of wristwatch may have an information processing unit incorporated therein. The information processing unit is formed with a microprocessor (MPU) for determining a diving situation, estimating the physical condition of a wearer, and instructing the wearer then diving. The wristwatch may be referred to as a dive computer or divers"" computer.
Some divers"" information processing apparatuses referred to as the dive computers perform arithmetic operations to calculate the conditions for decompression performed during diving. The calculating procedure is described in, for example, xe2x80x9cDive Computers: A consumer""s Guide to History, Theory, and Performancexe2x80x9d (Watersport Publishing Inc., 1991) written by Ken Loyst et al. Writings concerning the theory of decompression include xe2x80x9cDecompression: Decompression Sicknessxe2x80x9d (Springer, Berlin, 1984). Either writing implies that an inert gas (nitrogen) permeating a living body during diving causes decompression sickness. From the viewpoint of minimizing the occurrence of decompression, the latter writing has proposed on page 14 thereof a calculating procedure based on a formula (1) below.
Pigt(tE)=Pigt(t0)+{PIigxe2x88x92Pigt(t0)}xc3x97{1xe2x88x92exp[xe2x88x92ktE]}xe2x80x83xe2x80x83(1)
where Pigt(tE) denotes the partial pressure of an intracorporeal inert gas in a time interval tE, Pigt(t0) denotes the partial pressure of the intracorporeal inert gas in a time interval t0, PIig denotes the partial pressure of an inert gas in breath, and k denotes an experimentally determined constant.
The formula (1) is concerned with intake and discharge of an inert gas into and from a diver""s body. According to the formula (1), when the partial pressure of the intracorporeal inert gas, Pigt(t), is smaller than the partial pressure PIig, the inert gas is taken into the diver""s body and the partial pressure of the intracorporeal inert gas increases. When the partial pressure of the intracorporeal inert gas, Pigt(t), is larger than the partial pressure PIig, the inert gas is discharged from the diver""s body and the partial pressure of the intracorporeal inert gas therefore decreases.
When the partial pressure of the intracorporeal inert gas becomes equal to or larger than a certain pressure, a diver must ascend (decompress) slowly so as to minimize the occurrence of diver""s paralysis. At this time, the diver must manage an ascending speed or an ascending time until he/she rises to the surface of the water. Therefore, many information processing devices having the ability to estimate the partial pressure of a wearer""s intracorporeal inert gas and the ability to manage ascending so as to minimize the occurrence of diver""s paralysis have been proposed as the dive computer.
A facility for indicating an alarm so as to minimize the occurrence of diver""s paralysis and a facility for estimating the partial pressure of an wearer""s intracorporeal insert gas and indicating the partial pressure as physical information must be implemented without failure to avoid the dangers of diving. With a dive computer to be worn on a diver""s body, for example, a wristwatch-like dive computer, the area assigned to the display is limited. There is, therefore, difficulty in displaying all information at one time without impairment of discernment. For this reason, many conventional dive computers are designed to switch between a time mode, a plan mode, a surface mode, a log mode, and a dive mode depending on a situation or through manipulation performed by a wearer. In the time mode, a current year/month/day indication and a current time instant indication are displayed. In the plan mode, future diving is scheduled. In the surface mode, the partial pressure of an inert gases accumulated in a diver""s body due to past dives is indicated. In the log mode, the results of past dives are reproduced. In the dive mode, the physical condition such as the partial pressure of an intracorporeal inert gas is indicated during diving.
FIG. 8(a) and FIG. 8(b) illustratively show switching of modes of display permitted by a conventional wristwatch-like dive computer. In an example shown in FIG. 8(a), an external manipulation member is manipulated repeatedly in order to successively switch between the plan mode, surface mode, and log mode. Moreover, indications are switched merely between the surface mode and dive mode. In an example shown in FIG. 8(b), the surface mode, plan mode, and log mode are switched between one another. Similarly to the example shown in FIG. 8(a), indications are switched merely between the surface mode and dive mode. As indicated with a dotted line in the drawings, the time mode is normally unified with the surface mode or automatically switched to the surface mode or vice versa. For example, when the partial pressure of an intracorporeal inert gas is normal, the time mode is set automatically. When the partial pressure of an intracorporeal inert gas is higher than a normal pressure because of past dives, the surface mode is set automatically.
In the conventional dive computer, after diving is started, if ascending and diving are repeated, the dive computer also repeats the transition between the dive mode and the surface mode. When a diver ascends during diving, the diver may want to plan a subsequent diving schedule. In general, the partial pressure of an intracorporeal inert gas and the time required until the partial pressure of the intracorporeal inert gas returns to an equilibrium value are often indicated in the surface mode. In addition, a current time instant and a calendar may be indicated. However, a facility for indicating a diving depth (or a depth-of-water rank to be described later) and a diving enabled time (or a non-decompression diving enabled time to be described later) that are indicated in the plan mode is invalid in the surface mode. For planning s subsequent diving schedule on the surface of the water, the external manipulation member must be manipulated in order to change the surface mode to the plan mode temporarily. After planning is completed, the surface mode must be restored before diving is restarted.
Moreover, for making the most of the. foregoing dive computer offering numerous modes and having numerous facility, the contents of the display modes and facilities must be fully understood. Moreover, the complex way of manipulating the external manipulation member must be learned in order to utilize the display modes and facilities. The way of manipulation becomes complex as the facilities become complex. This poses a problem in that a user must incur a large load. In particular, when it is necessary to change a plurality of display modes as shown in FIG. 8, the small external manipulation member of the small wristwatch-like body must be manipulated many times. If a user forgets the manner of manipulation even partly, the user cannot make the most of the facilities of the dive computer.
The present invention attempts to solve the foregoing problems. An object of the present invention is to provide a divers"" information display device for a dive computer or the like. Herein, the present invention is intended to improve the manner of switching between a plurality of display modes or a plurality of facilities so as to thus improve the display feature of the display device, and to provide a configuration permitting easy switching of indications. More particularly, the present invention is intended to realize a technology for improving maneuverability sensed after the start of diving and upgrading the display feature.
For solving the above problems, the first feature in accordance with the present invention is implemented in a divers"" information display device having the ability to display a diving situation indication, a physical indication, and a diving schedule indication. Herein, the diving situation indication indicates a wearer""s diving situation. The physical indication indicates a physical state change that is attributable to wearer""s diving and calculated based on the diving situation. The diving schedule indication provides information assisting a wearer in planning a preferable diving schedule. In the divers"" information display device, a plan and surface mode in which the physical indication and diving schedule indication are displayed primarily, and a dive mode in which the diving situation indication is displayed primarily are implemented. When diving is started in the plan and surface mode, the plan and surface mode is automatically changed to the dive mode. When diving is terminated or suspended, the dive mode is automatically changed to the plan and surface mode.
According to the above feature, the plan and surface mode in which the physical indication and diving schedule indication are displayed is implemented. Even when a diver ascends during diving, the diver can grasp his/her physical condition and plan a diving schedule according to the physical condition without the necessity of switching display modes. Moreover, switching of indications between the plan and surface mode and the dive mode is automatically achieved at the start or end of diving or with suspension of diving. This almost completely obviates the necessity of performing manipulations during diving.
According to an aspect of the invention a time mode in which a time instant indication is displayed primarily is implemented. Preferably, when diving is started in the time mode, the time mode is automatically changed to the dive mode. Since the time mode is implemented, the diver""s information display device normally functions as a clock. Moreover, since the time mode is automatically changed to the dive mode, a diver can enjoy diving safely without making any preparations.
According to another aspect, a dive history memory is included for storing a history of wearer""s past dives. A log mode is implemented in order to retrieve and display the dive history. Preferably, when diving is started in the log mode, the log mode is automatically changed to the dive mode.
According to another aspect, first and second external manipulation members are included. Preferably, when the first external manipulation member is manipulated in any of the three modes of the time mode, plan and surface mode, and log mode, any of two display modes is changed to a first display mode. When the second external manipulation member is manipulated, any of two display modes is changed to a second display mode. Any of the three display modes can be changed to either of the other two display modes. One of the two external manipulation members need only be manipulated in order to change the display modes. This leads to improved maneuverability.
A The second feature in accordance with the present invention is implemented in a divers"" information display device having the ability to display a time instant indication, a diving situation indication, a physical indication, and a diving schedule indication. The diving situation indication indicates a wearer""s diving situation. The physical indication indicates a physical state change that is attributable to wearer""s diving and is calculated based on the diving situation. The diving schedule indication provides information assisting a wearer in planning a diving schedule according to the physical indication. The divers"" information display device includes a dive history memory for storing a history of wearer""s past dives, and first and second external manipulation members. A time mode, a plan and surface mode, a dive mode, and a log mode are implemented in the divers"" information display device. In the time mode, the time instant indication is primarily displayed. In the plan and surface mode, the physical indication and diving schedule indication are primarily displayed. In the dive mode, the diving situation indication is mainly displayed. In the log mode, the dive history is retrieved and displayed. When the first external manipulation member is manipulated in any of the three modes of the time mode, plan and surface mode, and log mode, either of two display modes is changed to a first display mode. When the second external manipulation member is manipulated, either of two display modes is changed to a second display mode.
According to another aspect, when the first external manipulation member is manipulated in the time mode, the time mode is changed to the plan and surface mode. Preferably, when the second external manipulation member is manipulated therein, the time mode is changed to the log mode. When the first external manipulation member is manipulated in the plan and surface mode or when the second external manipulation member is manipulated in the log mode, the time mode is restored. Among the three display modes, changing from the time mode to the plan and surface mode and restoring the time mode are achieved using the first external manipulation member all the time. Changing from the time mode to the log mode and restoring the time mode are achieved using the second external manipulation member all the time. Consequently, it is easy to learn the manner of manipulation and to store and preserve data. This leads to the easy-to-use divers"" information display device. p According to another aspect, preferably, when the second external manipulation member is manipulated in the plan and surface mode, the plan and surface mode is changed to the log mode. When the first external manipulation member is manipulated in the log mode, the log mode is changed to the plan and surface mode.
According to another aspect, preferably, when the first external manipulation member is manipulated in the time mode, the time mode is changed to the plan and surface mode. When the second external manipulation member is manipulated therein, the time mode is changed to the log mode. When the second external manipulation member is manipulated in the plan and surface mode, the plan and surface mode is changed to the log mode. When the first external manipulation member is manipulated in the log mode, the log mode is changed to the plan and surface mode. When the first external manipulation member is manipulated in any of the three display modes, the display mode is changed to the plan and surface mode. When the second external manipulation member is manipulated in any of the three display modes, the display mode is changed to the log mode. Consequently, the external manipulation member associated with a display mode to be selected need only be manipulated. It is therefore easy to learn the manner of manipulation and to store and preserve data. This leads to the easy-to-use divers"" information display device.
According to the foregoing feature, the practical examples of the diving situation indication include an indication of information relevant to a current dive or past and current dives. The information is classified into such items as a depth of water, a diving time (elapsed time since the start of diving), a maximum depth of water, and a water temperature. Moreover, the practical examples of the physical indication include an indication of information relevant to a physical condition dependent on diving. The information is classified into such items as the partial pressure of an intracorporeal inert gas, an intracorporeal inert gas discharge completion time (an estimated time required until the partial pressure of the intracorporeal inert gas reaches an equilibrium value), and an intracorporeal inert gas discharge time (time interval during which the intracorporeal inert gas is discharged, that is, a surface-of-water pause time). Furthermore, the practical examples of the diving schedule indication include an indication of information serving as an index for planning a future diving schedule according to the physical indication. The information is classified into such items as a depth of water to which a diver dives, and a non-decompression diving enabled time (time during which diving is enabled without the necessity of undergoing decompression during ascending). Moreover, the physical indication includes an indication relevant to an intracorporeal inert gas which is obtained through calculation according to a formula (for example, a formula 3 to be described later) devised based on experiments. According to the aforesaid feature, the plan and surface mode is automatically changed to the dive mode or vice versa at the time of the start, end, and suspension of diving. The start, end, or suspension of diving may be judged simply from whether a diver has plunged into water and withdrawn therefrom as it is in an embodiment described later. Otherwise, the start, end, or suspension of diving may be judged from whether a depth of water is larger or smaller than a predetermined depth of water. Moreover, the display modes may be changed in a predetermined time after the conditions for mode change are met.
According to the aforesaid feature, no external manipulation member may be manipulated for a predetermined time in the plan and surface mode or in the log mode among the three display modes of the time mode, plan and surface mode, and log mode. In this case, if an amount of intracorporeal inert gas is larger than that in a normal state, the plan and surface mode is maintained or the log mode is changed to the plan and surface mode. If the amount of intracorporeal inert gas assumes an equilibrium value, the plan and surface mode or log mode is changed to the time mode.
Aside from the aforesaid feature, another feature to be described in this description is implemented in an information display device offering a time mode in which a time instant is indicated. The information display device also offers a time difference correction mode in which a time difference derived from a wearer""s movement is corrected. The time difference correction mode enables correction of a time instant indication in units of a time suitable for correction of a time difference. The unit time is, for example, one hour, thirty minutes, or fifteen minutes. According to the feature, a manipulation to be performed for correcting a time difference can be simplified. Moreover, it prevents the time difference from being corrected in units of an improper time shorter than the unit time (for example, in N seconds) by mistake. This feature is preferably adapted to a divers"" information display device or a divers"" information processing apparatus. Preferably, this feature is combined with any of the aforesaid feature.